# `GSInstance setCustomValue:forKey:`

*Instance Method*

Sets the value for the custom parameter with the specified key.

## Declaration

```swift
func setCustomValue(_ value: Any?, forKey key: String)
```

```objc
- (void) setCustomValue:(id) value forKey:(NSString *) key;
```

```python
setCustomValue_forKey_(value: object, key: str)
```

## Parameters

- `value` — The value to set.
- `key` — The name of the parameter.

## Discussion

It will look for an existing parameter with the name and overwrite its value, or add a new parameter.